There has been a continuing need for a non-invasive means for the precise delivery of medicaments to selected sites in the animal alimentary canal. Generally, such delivery has taken the form of time delivery capsules, wherein a capsule containing the medicament is manufactured from a material that dissolves in a particular specific environment and/or within a particular time period within the alimentary canal; or, the form of elaborate mechanical devices that can be inserted into the alimentary canal by means of a mechanical tether or the like and can release the medicament at the desired location.
In dissolving type timed delivery capsule systems, the delivery of the medicament is highly dependent upon the predictability of the particular environment to which the capsule containing the medicament is subjected and nuances such as folds in the intestine, positions of the stomach which may create disruptions in passage of the capsule and the like. Dissolving type timed delivery capsules are widely used, but generally, because of the unpredictability of alimentary canal environment and the disruption of capsule passage caused by the geography of the canal, such capsules are seen as most useful for non-precise release of medicaments in general areas of the canal and are not seen as representing viable means for delivery to a specific site. Rarely are such means used when the release is intended to be limited to a specific site in the canal, such as at a particular tumor or the like.
Mechanical devices, are generally preferred when the release of the medicament is desired to occur at a specific site. Generally the mechanical devices which are used for such delivery are awkward implements, typically comprising long invasive needles or flexible tube mechanisms which are inserted into the alimentary canal with medicament release means at the inserted end. Flexible devices are typically "snaked" into the alimentary tract through the mouth, nose or anal opening and generally require anesthetizing procedures to be acceptable to the animal being treated. Release of the medicament at a specific site in the tract requires significant skill and typically must be done by a highly skilled physician using elaborate locating means such as miniaturized video, fluoroscopic, X-ray apparatus or the like.
The medical profession has long recognized the need for more reliable means for the delivery of medicaments to specific alimentary canal sites, particularly means that might be accurately and repeatedly accomplished without confining the patient to a medical facility and without requiring the intensity of medical professional attention now required by typically available mechanical means.
In recent years, "radio pill" technology has been described wherein a capsule, containing a transmitter, has been seen by the medical profession as a possible means to monitor various body environments. It has been suggested that such pills could be implanted, ingested or otherwise placed at desirable locations in the body and could be engineered to transmit critical data to a remote receiver located outside the body. The ideal radio pill is seen as one that is small enough to be easily ingested, biologically inert, disposable and inexpensive. The transmission signal would have to be sufficiently strong to be received by a remote receiver, preferably located apart from the patient's body so that the patient would have freedom of movement, or, be small enough to be carried by the patient.
As a result of such recent perceptions, researchers from Heidelberg University developed a capsule and system for monitoring pH of the gastrointestinal tract. This capsule and system, generally known as the Heidelberg pH capsule system, comprises a capsule containing a transmitter that is sensitive to pH changes experienced within the gastrointestinal tract. The patient wears a belt, which contains an antenna for collection of transmitted signals, which in turn feeds the signals to a receiver. The receiver stores and/or records the data, generally on a graph, thus providing the medical professional with a non-invasive means to monitor pH within the alimentary canal. Geographic location is not determined using the radio signals. Though the Heidelberg capsule system does allow some freedom of movement for the patient, it requires tethering of the patient to bulky machinery and has not enjoyed widespread commercial success, probably because of the limited use for the information gathered.
Another radio pill that has been recently developed is that generally known as the Konigsberg temperature telemetry pill. The Konigsberg pill is an ingestible capsule comprising a transmitter that is sensitive to temperature changes. As with the Heidelberg capsule, signals are transmitted to a collecting antenna and then to a receiver where the data is stored and/or recorded for use by the medical professional. Again, as with the Heidelberg capsule, geographic location of the capsule is not determined using the radio signals.
Each of the Heidelberg and Konigsberg capsules have utility in the short term monitoring of pH, but neither have the ability to deliver a drug at a selected site.
An object of the present invention is to provide a capsule which is easily ingestible in an animal alimentary canal and can be remote triggered to release medicament at a specified site in the canal.
Another object of the invention is to provide a capsule that can transmit a signal to a remote receiver, sufficient to determine geographic location of the capsule within the alimentary canal.
A further object of the invention is to provide a process for the tracking of a capsule through the alimentary canal.
A still further object of the invention is to provide a process for tracking a capsule through the alimentary canal and releasing a desired dosage of medicament at a specified site within the canal.
These and other objects of the invention will become apparent from the following description of the invention.